title: Preoperative stenting decreases operative time and reoperative rates of ureteroscopy.
abstract: OBJECTIVE
  Large stone burden can be treated ureteroscopically, but the treatment often requires more than one procedure. Placement of a preoperative stent may theoretically enhance stone clearance by dilating the ureter to facilitate both access and stone removal. This study determines the impact of stent placement before ureteroscopy on operative time, radiologic stone clearance, and reoperative rates.
  
  
  METHODS
  We retrospectively reviewed the records of patients who underwent ureteroscopic stone intervention at our institution from 2002 to 2008 by a single surgeon. Nonstented matched controls were used for comparison. Demographics, stone characteristics (size, number, density, and location), presence of preprocedural ureteral stent, operative time, and results of postoperative imaging were compared between the two cohorts. Statistical analysis was performed.
  
  
  RESULTS
  There were 104 patients included in the study (45 prestented and 59 nonstented). Median stone size was 1 cm (range 0.3-4 cm). Overall stone clearance was 95.8%. The median number of procedures was one. Prestenting significantly reduced operative time during first ureteroscopy in patients with large stone requiring multiple ureteroscopies (p = 0.008) and total operative time to stone clearance in patients with stone >1 cm (p = 0.01), but not in patients with stone burdens <1 cm (p = 0.48). Prestenting also significantly reduced reoperative rates in patients with stone burden >1 cm (p = 0.001), especially for stones located in proximal ureter and kidney. Prestenting improves postoperative radiologic clearance, but this was not statistically significant (p = 0.56).
  
  
  CONCLUSIONS
  Results show that ureteroscopic lithotripsy of large stone burden can be performed with a high success rate. Preureteroscopic stent placement was associated with a decreased operative time and reoperative rates in patients with larger stone burdens of >1 cm.
authors.affiliation: Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA. chul@upmc.edu
authors.forename: Lei
authors.initials: L
authors.lastname: Chu
authors.forename: Kevan M
authors.initials: KM
authors.lastname: Sternberg
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Averch
mesh_terms: D015331:Cohort Studies; D003710:Demography; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012086:Reoperation / Q000706:statistics & numerical data*; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D018666:Ureteroscopy / Q000379:methods*